Diagnosis of Alzheimers Disease

Diagnostic Tests

Your doctor will ask about your symptoms and medical history. A physical exam will be done. This includes a thorough neurological evaluation along with a series of tests. Other tests may include those which will increase or decrease the likelihood that you have Alzheimers disease. Your doctor will also perform tests to eliminate the possibility of other conditions causing the dementia.

Tests to Assess Dementia

These tests help determine if you have signs of dementia, how severe the dementia is, or to look for other causes of dementia. They may include:

Neurological exam—examines the nervous system for evidence of other neurological disorders. This may include mental status testing of:

Memory

Sense of time and place

Problem-solving abilities

Attention span

Language skills

Visual-spatial perception

Learning capacity

Judgement

Decision-making skills

Psychological evaluation—looks for depression or other emotional illnesses that may be the first sign of Alzheimers disease

Imaging tests, such as
MRI,
CT, and/or
PET scans—to evaluate the brain for any abnormalities

Lumbar puncture—tests the fluid surrounding the brain and spinal cord to look for infections that can cause dementia, or show markers of Alzheimers, such as beta amyloid and tau proteins

Additionally,
electroencephalogram
(EEG)
is a test that evaluates and follows the electrical activity of the brain. It is not a common test for evaluating most dementias, but it may be done.

Blood and Urine Tests

Blood and urine tests may be ordered to look for other conditions that cause dementia. The tests may include:

Genetic Tests

Genetic tests can look for markers that increase your risk for early-onset Alzheimers. Your doctor may recommend this test if you have family members with this condition.

Diagnostic Categories

An Alzheimers disease diagnosis usually falls into one of three categories:

Probable Alzheimers disease—This indicates that other dementia-related disorders have likely been ruled out. The symptoms are most likely due to Alzheimers disease. At least 2 areas of cognition are affected. One area is a worsening of memory.

Possible Alzheimers disease—The dementia is possibly caused by Alzheimers disease. There may be other disorders that are causing the dementia.

Definite Alzheimers disease—This diagnosis can only be made at the time of death. It is done through an autopsy when the brain tissue can be examined. This is the only way to diagnose the disease with complete certainty.

Revision Information

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.